Ebook Coronary artery bypasses: Part 1

Cardiology Research and Clinical Developments

CORONARY ARTERY BYPASSES

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CARDIOLOGY RESEARCH AND CLINICAL
DEVELOPMENTS
Focus on Atherosclerosis Research
Leon V. Clark
2004 ISBN: 1-59454-044-6

Heart Disease in Men
Alice B. Todd and Margo H. Mosley
2009 ISBN: 978-1-60692-297-2

Cholesterol in Atherosclerosis and
Coronary Heart Disease
Jean P. Kovala
2005 ISBN: 1-59454-302-X

Angina Pectoris: Etiology, Pathogenesis
and Treatment

Alice P. Gallos and Margaret L. Jones
2009 ISBN: 978-1-60456-674-1

Frontiers in Atherosclerosis Research
Karin F. Kepper
2007 ISBN: 1-60021-371-5

Coronary Artery Bypasses
Russell T. Hammond and James B Alton
2009 ISBN: 978-1-60741-064-5

Cardiac Arrhythmia Research Advances
Lynn A. Vespry
2007 ISBN: 1-60021-794-X

Congenital Heart Defects: Etiology,
Diagnosis and Treatment
Hiroto Nakamura
2009 ISBN: 978-1-60692-559-1

Heart Disease in Women
Benjamin V. Lardner and Harrison R.
Pennelton
2009 ISBN: 978-1-60692-066-4
Cardiomyopathies: Causes, Effects and
Treatment
Peter H. Bruno and Matthew T. Giordano
2009 ISBN: 978-1-60692-193-7
Estrogen and Myocardial Infarction
Jiang Hong, Chen Jing, He Bo,

and Lu Zhi-bing
2009 ISBN: 978-1-60692-257-6

Atherosclerosis: Understanding
Pathogenesis and Challenge for Treatment
Slavica Mitrovska, Silvana Jovanova Inge
Matthiesen and Christian Libermans
2009 ISBN: 978-1-60692-677-2
Practical Rapid ECG Interpretation
(PREI)
Abraham G. Kocheril and Ali A. Sovari
2009 ISBN: 978-1-60741-021-8


Cardiology Research and Clinical Developments

CORONARY ARTERY BYPASSES

RUSSELL T. HAMMOND
AND

JAMES B. ALTON
EDITORS

Nova Biomedical Books
New York


Copyright © 2009 by Nova Science Publishers, Inc.
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BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF
PUBLISHERS.
Library of Congress Cataloging-in-Publication Data
Coronary artery bypasses / [edited by] Russell T. Hammond and James B. Alton.
p. ; cm.
Includes bibliographical references and index.
ISBN 978-1-61728-209-6 (E-Book)
1. Coronary artery bypass. I. Hammond, Russell T. II. Alton, James B.
[DNLM: 1. Coronary Artery Bypass. WG 169 C8216 2009]
RD598.35.C67C687 2009

617.4'12--dc22
2009000159

Published by Nova Science Publishers, Inc. 
  New York


Contents
Preface
Chapter I

Chapter II

Chapter III

vii
Use of Radial Artery Grafts in Myocardial Revascularization
Surgery: Laboratory and Clinical Evidence in the Last 20 Years
Chee Fui Chong
A New Horizon for Coronary Surgery: Hybrid Coronary
Revascularization and Routine Intra-Operative Completion
Angiography
Marzia Leacche, Annemarie Thompson, David X. Zhao, Bernhard
J. Riedel and John G. Byrne
Coronary Sinus in Cardiac Surgery: The Alternative Route
to Protect, Predict and Heal
Francesco Onorati, Antonino S. Rubino, Giuseppe Santarpino
and Attilio Renzulli

Chapter IV

Acute Kidney Injury after Coronary Artery Bypass
M. Guillouet, B.V. Nguyen, F. Lion, R. Deredec, C.C. Arvieux
and G. Gueret

Chapter V

Coronary Artery Bypass Grafting for Chronic and Acute
Heart Failure
Marco Pocar, Andrea Moneta, Davide Passolunghi,
Alessandra Di Mauro, Alda Bregasi,
Roberto Mattioli and Francesco Donatelli

Chapter VI

Postoperative Constrictive Pericarditis –Present Approach
M. Bergman, Z. Z. Brener and H. Salman

Chapter VII

Coronary Revascularization in Patients with Diabetic Retinopathy:
From Cardiac Surgeons’ Perspective
Takayuki Ohno

1

51

69

81

111

123

135


vi
Chapter VIII

Chapter IX

Chapter X

Chapter XI
Index

Contents
Myocardial Revascularization with and without Extracorporeal
Circulation
Whady A. Hueb and Neuza H. M. Lopes

147

Quality of Life and Coronary Artery Bypass Surgery:
A Longitudinal Study
Geraldine A. Lee

161

Cognitive Function and Cerebral Perfusion in off-Pump
and on-pump Coronary Artery Bypass Patients
Vladimir I. Chernov, Nataliya Yu. Efimova, Irina Yu. Efimova,
Shamil D. Akhmedov and Yuri B. Lishmanov
The Influence of Male Gender in Coronary Bypass Surgery
Justin Blasberg and Sandhya K. Balaram

211

227
241


Preface
Coronary bypass surgery is a procedure to allow blood to flow to the heart muscle
despite blocked arteries. Coronary bypass surgery uses a healthy blood vessel taken from
your leg, arm, chest or abdomen and connects it to the other arteries in the heart so that blood
is bypassed around the diseased or blocked area. After a coronary bypass surgery, normal
blood flow is restored. Coronary bypass surgery is just one option to treat heart disease. This
new book presents the latest research in this growing field.
Chapter I - In the last two decades, we have seen the evolution of the radial artery (RA)
graft in myocardial revascularization surgery from the time when it was first re-introduced as
an arterial conduit in 1992. It is now regularly harvested in some centres as a second arterial
conduit in combination with the pedicled left internal thoracic artery (LITA) graft. It has
outlived other arterial conduits introduced in the 1980s, such as the right gastroepiploiac
(RGEA) and inferior epigastric (IEA) arteries.
Its use has been driven by the demand for better long-term graft survival, as proven by
the LITA graft, and also with the increasing incidence of re-operative myocardial

revascularization surgery in patients with exhausted venous reserve. The significantly better
long-term patency of the LITA graft has provided the impetus for achieving complete arterial
revascularization. Since the 1980s, several arterial grafts have been tried and abandoned due
to technical difficulties and, more importantly, because patency rates achieved were inferior
to the LITA graft. RA grafts have stood out so far, and the improvement in patency rates of
RA grafts have largely been due to a better understanding of their morphology, receptor types
and vasoreactivity properties, leading to the introduction of various vasorelaxants such as
calcium channel blockers, alpha receptor blockers, papaverine and GTN to prevent graft
vasospasm. Improvements in harvesting and graft preparation techniques have also
contributed greatly to a reduction in peri-operative and post-operative graft spasm and hence
improvement in patency rates.
Besides laboratory evidence, in-vivo vasoreactivity studies of RA grafts have shown
preservation of endothelium function three months after surgery, as well as adaptation of their
vasoreactivity characteristics and diameter similar to those seen in the target coronary artery
five years later. This ability of the RA graft to autoregulate and adapt its vasoreactivity and
diameter characteristics closely resembles those observed in LITA several years after CABG,
indicating that it is a viable and living conduit.


viii

Russell T. Hammond and James B. Alton

However, for RA grafts to make any impact on coronary artery bypass grafting as an
arterial conduit, clinical evidence of superior patency rates over the saphenous vein (SV)
grafts must be available. Over the last two decades, there have been numerous observational
studies and three randomized controlled trials assessing the early patency rates of RA in
comparison to SV grafts. These trials have reported satisfactory early RA graft patency of
three to twelve months on the order of more than 90%, and are significantly better than SV
grafts. Observational studies have also reported satisfactory mid-term five-year patency rates

for RA grafts, and data from randomized studies are now available with the recent
publication of the results of the RAPCO and RSVP trials. This chapter reviews the progress
that has been made over the last two decades since the resurgence of interest in RA grafts,
and discusses the important anatomical anomalies with regards to harvesting, improvement of
current techniques of harvesting and grafting, and current available laboratory and in-vivo
evidence on the vasoreactivities of RA grafts, as well as clinical evidence on the patency
rates of RA grafts.
Chapter II - Hybrid coronary revascularization combines coronary artery bypass grafting
(CABG) surgery with percutaneous coronary intervention (PCI) for coronary artery disease.
Surgical grafting is reserved for revascularization of the left anterior descending (LAD)
artery, usually performed with the left internal mammary artery (LIMA) through either a
limited thoracotomy or an endoscopic approach, while PCI with stenting is reserved for
revascularization of non-LAD lesions. This combines the benefits of each technique—
namely, the superiority of the LIMA to LAD graft and the improved patency rate of stent
placement in non-LAD vessels. For non-LAD vessels, the higher one-year failure rate for
saphenous vein grafts (SVG, averages 20%) compared to drug-eluting stents (DES, average
9%) supports this hybrid approach.
The hybrid procedure can be performed as a staged procedure—with PCI followed by
CABG or CABG followed by PCI. However, hybrid coronary revascularization is
increasingly performed as a combined (“one stop”) procedure in a dedicated suite—the
“hybrid operating room”. The hybrid room has the capability of serving both as a complete
surgical operating room and as a catheterization laboratory.
The hybrid operating room also allows for routine completion angiography following
CABG surgery. This facilitates early identification of graft failure thereby providing the
opportunity to correct technical errors within the same surgical period and thus may improve
graft patency rate, especially of SVG to non-LAD vessels.
This chapter reviews the advantages of and the logistics required for performing hybrid
procedures and completion angiography—a new horizon for coronary surgery.
Chapter III - The coronary surgical population has changed during the last decades: the
patients are elderly, with extensive coronary disease, poor ventricular function, congestive

heart failure, and/or ongoing ischemia. Therefore, myocardial protection nowadays is a
surgical challenge. In particular, we look to the coronary sinus as a novel tool to enhance
myocardial protection in different scenarios. Since Buckberg demonstrated blood as the best
cardioplegic vehicle in ischemic myocardium, and later introduced retroplegia into clinical
practice, we routinely add retroplegia to traditional antegrade cardioplegia and have found a
significantly lower troponin leakage and better myocardial performance both in routine
coronary surgery and in high-risk subgroups, such as diabetes, left ventricular hypertrophy


Preface

ix

and severe coronary disease. Apart from this use, we have found intraoperative levels of
troponin I (TnI) and lactate sampled directly from the coronary sinus via the retroplegia
cannula to predict cardiac complication during hospitalization and short-term follow-up. The
opportunity for intraoperative testing of highly sensitive and specific markers of myocardial
dysfunction improves the safety of cardiac surgery by mandating preventive strategies to
reduce further myocardial damage whenever an intraoperative rising level of TnI or lactate is
detected. Finally, we use the coronary sinus to deliver warm autologous blood during the
time of surgery whenever catastrophic complications (such as cardiac arrest or cardiogenic
shock) occur intraoperatively or in patients already admitted to the hospital but waiting for
surgery. Again, coronary sinus retroperfusion (CSRP) has never led to TnI elevation
(suggestive of acute myocardial infarction), indicating an impressive protective effect of
CSRP on the ischemic myocardium. On the other hand, when CSRP was avoided, a
significantly higher lactate production was found, and a higher rate of perioperative death,
acute myocardial infarction, low-output syndrome, and a need for prolonged inotropic and/or
IABP support was recorded.
These data suggest a novel role for coronary sinus interventions in modern cardiac
surgery: combined antegrade and retrograde cardioplegia should be regarded as a planned

strategy to better protect the myocardium; TnI and lactate sampled from the coronary sinus
proved to be a valid diagnostic tool in early detection of myocardial damage and acute
myocardial infarction; retroperfusion represents a therapeutic root for rapid recovery of
viable myocardium in of sudden cardiac arrest or cardiogenic shock in the early phases of
cardiac surgery.
Chapter IV - Acute kidney injury (AKI) is common after cardiac surgery with
cardiopulmonary bypass (CPB). Previous studies have reported an incidence from 3 to 30%
according to the authors and the different criteria considered [1-4]. The percentage of patients
with AKI requiring dialysis may vary from 0.5 to 3% according to certain studies [5-12].
Post-operative AKI after cardiac surgery with CPB correlates with an increased length of stay
in the intensive care unit (ICU) [5]. It is also associated with a high mortality rate (up to 60%)
when dialysis is required [3,5,13]. Risk factors like female gender, diabetes, chronic
obstructive pulmonary disease, congestive heart failure, length of surgery and age have been
identified [14], and one of the most important factors seems to be chronic renal failure before
surgery, even if this last association although requiring further research, has been universally
accepted [15].
Recently, studies have demonstrated the association of genetic polymorphisms with a
risk of renal injury. The genetic variants identified are associated with increases in renal
inflammatory response through exagerated synthesis in the IL6 protein [16]. There is also
genetic predisposition.
AKI in CPB is the consequence of a mixture of several physiopathological phenomena,
among which we find systemic inflammatory response syndrome (SIRS).
Cardiac bypass surgery activates the inflammatory cascade and leads to systemic
inflammatory response syndrome through the phenomenon of ischemia-reperfusion. Indeed,
initially, we can observe an imbalance between pro- and anti-inflammatory factors as well as
between factors of vasoconstriction. Secondly, neutrophils, vascular endothelium and
platelets are activated. These events lead to capillary microthrombosis and the elaboration of


x

Russell T. Hammond and James B. Alton

inflammatory mediators such as IL-6, IL-8 and TNF α. These cytokines are both synthetised
systemically and locally in the kidney. They are responsible for tubular necrosis, apoptosis,
and glomerular injury. Serum creatinine and perioperative urinary output which are routinely
used to evaluate the underlying renal status of the patient are not sensitive and specific
enough in the detection of the early phases of this condition. New biomarkers, including
neutrophil gelatinase, associated lipocalin, interleukin 18 and kidney injury molecule 1 seem
promising.
Thus, we can hope that a better knowledge of all of the mechanisms leading to acute
renal dysfunction after coronary artery bypass and the use of new renal injury biomarkers
may reduce the negative consequences of AKI.
Chapter V - The techniques and reproducibility of surgical coronary revascularization
rely on over forty-year experience. However, surgery for ischemic heart disease with
associated left ventricular dysfunction carried high if not prohibitive operative risk during the
pioneering and early era of coronary surgery. Although the benefits of revascularization in
this context have been well documented, the propensity to operate on patients with heart
failure still often relies on concurrent anginal symptoms. Similarly, many surgeons are
reluctant to offer surgery aimed to reverse low cardiac output during acute or evolving
myocardial infarction.
The purpose of this chapter is to depict up-to-date strategies and attitudes toward
coronary operations in chronic or acute heart failure, focusing on personal experience with
ischemic cardiomyopathy and acute coronary syndromes complicated by pump dysfunction
or shock. Emphasis will be given to the selection of patients, evolving technology, technical
strategies, and ultimately to the limitations of isolated coronary revascularization and the
increasing role of associated surgical procedures in ischemic cardiomyopathy.
Chapter VI - Cardiac surgery, including coronary artery bypass, has become one of the
foremost causes for development of constrictive pericarditis in developed countries. This
article reviews the updated understanding of the etiology, physiology, clinical presentation,

diagnosis, prognosis and treatment of postoperative pericardial constriction. One of the
typical clinical signs suggestive for constrictive pericarditis is development of right side heart
failure due to development of a thick and non-elastic pericardium. Postoperative constrictive
pericarditis as an early or late complication of heart surgery presents either as an isolated
phenomenon, or as a multisystem disorder. Since the clinical findings are often
misinterpreted, the patients are treated by physicians from different specialties, and therefore
the correct diagnosis may be overlooked. Occasionally, achieving proper diagnosis requires
application of invasive cardiological procedures. Early detection of post-surgical pericardial
constriction is of great importance for both physicians, hospitalists, cardiac and thoracic
surgeons in order to administer proper treatment.
Chapter VII - Coronary artery disease is the leading cause of death in the diabetic
population. Therefore, the main purpose of managing of coronary heart disease should be to
lengthen life expectancy. Recent evidence demonstrates that severity of diabetic retinopathy
is associated with a graded, increased risk of death from coronary artery disease and
myocardial infarction. First, I review published studies evaluating the association between
diabetic retinopathy and CAD. Second, I propose that coronary artery bypass surgery would
be the first choice for revascularization of patients with diabetic retinopathy, especially in


Preface

xi

early-stage retinopathy. Furthermore, coronary artery disease in patients with diabetic
retinopathy is most often underdiagnosed, and all patients with diabetic retinopathy should
undergo screening for coronary artery disease followed by CABG. Therefore, we initiated the
Diabetic Retino-Coronary Heart Clinic for diabetic retinopathy patients in April 2007. The
aims of this clinic were (1) targeted diagnosis and treatment of CHD for patients with
diabetic retinopathy, and (2) to improve life expectancy of the diabetic population. CHD was
diagnosed according to our protocol using treadmill stress test, coronary CT, scintigram, and

coronary angiography. Finally, I describe our experience from the clinic.
Chapter VIII - Coronary bypass surgery performed without the use of cardiopulmonary
bypass (off-pump surgery) has been used sporadically since the beginning of the bypass
surgery era in 1967, but the use of this strategy increased substantially during the 1990s [1].
The major reason for the increased use of off-pump surgery was the hope that this strategy
would decrease perioperative morbidity and possibly mortality by eliminating
cardiopulmonary bypass (on-pump surgery). The apprehension concerning off-pump surgery
has been that the difficulty of operating with the heart beating may lead to less-complete and
less-effective revascularization at the time of surgery and worse long-term outcomes. The
advantages and disadvantages have been examined in several studies comparing the
outcomes of patients undergoing off-pump and on-pump surgery. Follow-up studies, both
randomized and observational, have sometimes noted inferior long-term outcomes after offpump surgery compared with on-pump surgery, such as decreased patency, increased risk of
repeat revascularization, or increased mortality. Other studies [2-4] have shown no long-term
differences. When present, these differences usually have not been large and often have been
attributed to the surgeon’s lack of experience with off-pump surgery.
Chapter IX - INTRODUCTION: Cardiovascular disease (CVD) remains a significant
worldwide health problem leading to premature death and chronic illness with Coronary heart
disease (CHD) accounts for 52% of CVD cases with 16 million cases of CHD in the US. One
of the treatment options for those with CHD is Coronary Artery Bypass Surgery (CABG).
The aim of the surgery is to alleviate symptoms such as angina and breathlessness, prevent
further Myocardial Infarctions (MIs) and reduce the progression of CHD.
METHOD and AIM OF STUDY: A study was undertaken in the United Kingdom five
years after CABG. Patients from a previous study agreed to participate in a follow-up study
five years after cardiac surgery. Participants were asked to complete a quality of life
questionnaire, the Short-Form 36 (SF-36) and questionnaires on their psychological wellbeing (anxiety and depression symptoms). Neuropsychological assessment was also
performed at the follow-up. The assessments of psychological well-being and
neuropsychological tests were previously completed prior to surgery.
RESULTS: One hundred and nine patients were interviewed face-to-face. The SF-36
component summaries of the patients indicated that their physical (PCS) and mental (MCS)
health was relatively good (45.8 and 53.6, respectively, with 0 = worst health and 100 = best

health and 50 being the mean score). Lower PCS scores were associated with comorbid
illness. Psychological well-being (anxiety and depression) was found to correlate with the
SF-36 physical and mental component summaries (p < .001) at the time of follow-up.
Deficits in neuropsychological scores five years post CABG were found in 28% of the
patients with no correlation between the SF-36 component summaries and the


xii

Russell T. Hammond and James B. Alton

neuropsychological assessment five years after CABG suggesting that these deficits do not
interfere with patient perceived HRQoL.
DISCUSSION: The significance of psychological well-being were highlighted in the
hierarchical regression analysis with pre-operative angina scores and the following data five
years post CABG; comorbid illness, anxiety and depressive symptoms and physical activity,
accounting for 37% of the variance in PCS. Pre-operative anxiety, interim myocardial
infarction and the following data five years post CABG: age, diet scores, anxiety and
depression symptoms, accounted for 60% of the variance in MCS.
CONCLUSION: The findings demonstrate that patient perceived HRQoL five years after
CABG is generally good. However, it is negatively affected the presence of anxiety or
depression symptoms at follow-up. The findings have implications for healthcare
professionals and highlight the importance of anxiety and depression after surgical
revascularisation.
Chapter X - Objective: The aim of this study was to evaluate cognitive function, as
measured by serial neuropsychologic testing, and cerebral perfusion, as measured by brain
SPECT scanning in coronary artery diseases (CAD) patients following off-pump and onpump coronary artery bypass graft surgery. Besides the relationship between cerebral blood
flow, cognitive functions, surgery parameters and cardiac function in these patients were
estimated. Also brain-protective effects of instenon were studied.
Methods: Brain SPECT and comprehensive neuropsychological testing were performed 1

day before, 10-14 days and 6 months after coronary artery bypass graft surgery (CABG). The
study involved 65 patients (62 males and 3 females, mean age 55+2) underwent CABG with
cardiopulmonary bypass (CPB) (43pts) and off-pump coronary revascularization (OPCAB)
using the Octopus stabilisation system (22pts). In 21 cases employing CPB for prevention the
impairments of cerebral perfusion and cognitive deficit was administered instenon.
Results: CABG with use of extracorporeal circulation is complicated by short-term and
long-term neurocognitive dysfunction (in 96% and in 55% cases, correspondingly). Also in
the early period after CABG in 68% patients decrease in regional cerebral blood flow (rCBF)
was found and after 6 months brain perfusion was lower than baseline in 55% cases.
Relationship between postoperative rCBF changes and dynamic of cognitive function was
found in the early period and after 6 months following CABG.
Conclusion: The coronary revascularisation on the beating heart or preventive
administration of instenon in CPB patients helps significantly to diminish the risk of
cerebrovascular complication.
Chapter XI - Over the past fifteen years, gender studies in coronary artery bypass graft
(CABG) surgery outcomes have focused on women, although the majority of patients
diagnosed with coronary artery disease and those who undergo intervention are
predominantly male. A marked increase in public interest in women’s health accompanied by
new scientific research has produced increasing evidence that women carry a higher
operative mortality after CABG surgery. The fact that this data remains somewhat
controversial emphasizes the complexity of the issue. It has become clear that differences in
profiles between men and women contribute to variation in outcomes after CABG. Biologic
differences play a role in etiology, progression, and treatment outcomes. Furthermore, some
risk factors have been shown to be unique to each gender. Ultimately, determination of


Preface

xiii

specific independent predictors for long-term mortality after CABG may be helpful in
improving surgical results. The purpose of this chapter is to summarize and analyze the
current body of knowledge of male gender as an independent variable in coronary artery
bypass surgery.



In: Coronary Artery Bypasses
Editors: Russell T. Hammond and James B. Alton

ISBN: 978-1-60741-064-5
©2009 Nova Science Publishers, Inc.

Chapter I

Use of Radial Artery Grafts
in Myocardial Revascularization
Surgery: Laboratory and Clinical
Evidence in the Last 20 Years
Chee Fui Chong*
Thoracic Unit, Department of General Surgery,
Raja Isteri Pengiran Anak Saleha Hospital, Bandar Seri Begawan BA1710,
Brunei Darussalam

Abstract
In the last two decades, we have seen the evolution of the radial artery (RA) graft in
myocardial revascularization surgery from the time when it was first re-introduced as an
arterial conduit in 1992. It is now regularly harvested in some centres as a second arterial
conduit in combination with the pedicled left internal thoracic artery (LITA) graft. It has
outlived other arterial conduits introduced in the 1980s, such as the right gastroepiploiac

(RGEA) and inferior epigastric (IEA) arteries.
Its use has been driven by the demand for better long-term graft survival, as proven
by the LITA graft, and also with the increasing incidence of re-operative myocardial
revascularization surgery in patients with exhausted venous reserve. The significantly
better long-term patency of the LITA graft has provided the impetus for achieving
complete arterial revascularization. Since the 1980s, several arterial grafts have been
tried and abandoned due to technical difficulties and, more importantly, because patency
rates achieved were inferior to the LITA graft. RA grafts have stood out so far, and the
improvement in patency rates of RA grafts have largely been due to a better
understanding of their morphology, receptor types and vasoreactivity properties, leading
to the introduction of various vasorelaxants such as calcium channel blockers, alpha
*

Correspondence to: Mr Chee Fui Chong, BSc MBBS FRCSEd(CTh) MD(Lond); Consultant, Cardiovascular and
Thoracic Surgeon, Thoracic Unit, Department of General Surgery, RIPAS Hospital, Bandar Seri Begawan BA
1710, Brunei Darussalam. Hp: +673-8185932; Fax: +673-2333270; Email:


2

Chee Fui Chong
receptor blockers, papaverine and GTN to prevent graft vasospasm. Improvements in
harvesting and graft preparation techniques have also contributed greatly to a reduction
in peri-operative and post-operative graft spasm and hence improvement in patency rates.
Besides laboratory evidence, in-vivo vasoreactivity studies of RA grafts have shown
preservation of endothelium function three months after surgery, as well as adaptation of
their vasoreactivity characteristics and diameter similar to those seen in the target
coronary artery five years later. This ability of the RA graft to autoregulate and adapt its
vasoreactivity and diameter characteristics closely resembles those observed in LITA
several years after CABG, indicating that it is a viable and living conduit.

However, for RA grafts to make any impact on coronary artery bypass grafting as an
arterial conduit, clinical evidence of superior patency rates over the saphenous vein (SV)
grafts must be available. Over the last two decades, there have been numerous
observational studies and three randomized controlled trials assessing the early patency
rates of RA in comparison to SV grafts. These trials have reported satisfactory early RA
graft patency of three to twelve months on the order of more than 90%, and are
significantly better than SV grafts. Observational studies have also reported satisfactory
mid-term five-year patency rates for RA grafts, and data from randomized studies are
now available with the recent publication of the results of the RAPCO and RSVP trials.
This chapter reviews the progress that has been made over the last two decades since the
resurgence of interest in RA grafts, and discusses the important anatomical anomalies
with regards to harvesting, improvement of current techniques of harvesting and grafting,
and current available laboratory and in-vivo evidence on the vasoreactivities of RA
grafts, as well as clinical evidence on the patency rates of RA grafts.

Background
The radial artery (RA) was first introduced as an alternative arterial conduit in the early
1970s by Carpentier [1]. However, unforeseen early graft vasospasm led to an alarmingly
high occlusion rate of 35% at three months to one year. A similar problem of vasospasm was
also encountered by Fisk et al. and Curtis et al. [2;3]. Two years later, the RA was completely
abandoned as a suitable arterial conduit. Vasospasm of the RA graft was concluded to be due
to denervation of the arterial pedicle and trauma associated with the harvesting, especially
skeletonization and preparation [2;3].
It was not until two decades later, in the late 1980s, that Carpentier received reports of an
angiogram showing a patent RA graft which was previously thought to be occluded at the
initial angiogram fifteen years before. He restudied nine patients with reported RA graft
occlusion from his initial study and found that eight out of nine of the RA grafts were now
patent [4].
By the turn of this decade, work by Furchgott and Zawadzki revealed the importance of
the vascular endothelium and its multitude of functions in maintaining vessel function and

integrity through nitric oxide (NO) synthesis and release [5]. By performing mechanical
dilatation to the RA conduit, Carpentier had unknowingly destroyed the endothelium, causing
the observed vasospasm and high graft occlusion rate in his initial series in the 1970s [1].
This realization, combined with the possibility of long-term patency of RA grafts, sparked a
resurgence of interest in the RA as an arterial conduit in the early 1990s.


Use of Radial Artery Grafts in Myocardial Revascularization Surgery…

3

Since then, there has been an explosion of interest in its use with recent publications of
results from three prospective randomized controlled clinical trials of early and long-term
patency rates of RA grafts compared to saphenous vein (SV) grafts. Data from these trials
have confirmed significantly better early one-year and late five-year patency rates for RA
grafts compared with SV grafts, and secured its position as a second arterial conduit
following the LITA graft.

Anatomy and Congenital Anomaly of the RA
The RA is highly suited for harvesting as a conduit for CABG for several reasons. First,
its superficial location in the forearm makes it easy to harvest (figure 1) [4;6]. Second, the
length of a fully-harvested RA (20–22 cm) can reach any coronary targets and at best can be
divided to provide two grafts [7]. Third, it is an arterial conduit like the pedicled LITA.

Figure 1. Radial Artery Pedicle: The RA pedicled beneath the brachioradialis muscle is exposed by
retracting the medial surface of the brachioradialis muscle with a small West self-retractor.

The RA begins about 1 cm below the elbow crease with the division of the brachial
artery into the RA and ulnar artery (UA) [8]. The proximal two-thirds of the RA lies under
the brachioradialis muscle, while the distal third is superficial, covered only by deep fascia,

subcutaneous fat and skin before it enters the hand through the carpal tunnel [6]. The RA
with its two venae comminantes travel down the forearm nestled between the brachioradialis
above and successively on the biceps tendon, supinator, pronator teres, flexor digitorum
superficialis, flexor pollicis longus, pronator quadratus and the distal end of the radius
beneath (figure 1) [8]. It gives off numerous muscular side branches along the way and
distally, the lateral antebrachial nerve lies immediately lateral to the vascular pedicle. Two


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Chee Fui Chong

important branches need to be conserved during harvesting and these are the recurrent radial
branch proximally and the superficial recurrent palmar artery distally, usually after the level
of the radial styloid process [6]. In the hand, the RA and UA form an extensive network of
collateral via the deep and superficial palmar arches.
Unlike the other arterial grafts used, congenital anomalies of upper limbs arterial system
are more frequent and well documented. In a study of 750 upper limbs, McCormark reported
18% incidence of forearm arterial anomalies of which a large majority (77%) consists of a
high origin of RA from the axillary artery [9]. This variation is usually associated with a
normal anatomical course in the forearm and no hand anomalies. Therefore complete
harvesting may provide two length of conduit [10].
Other forearm arterial anomalies, particularly bilateral congenital absence of UA may
result in hand ischemia if the RA is harvested for conduit as in the case which was reported
by Fox et al. [11]. A low division of brachial artery under the pronator teres muscle has also
been described and is associated with an abnormal and shorten course of the RA in the
forearm through the pronator teres muscle [10;12-14]. Harvesting of this artery may be
associated with a much shorter conduit.
In the hand, reported frequency of incomplete superficial palmar arches can range from
6% to 34% and harvesting of RA in such cases can result in vascular insufficiency in the

donor hand, which may require a rescue interposition saphenous vein or gortex graft to
replace the harvested RA.

Clinical Assessments
of Ulnar Collateral Circulation
Preoperative Assessment Using Modified Allen’s Test
The most commonly used preoperative screening test to assess sufficiency of ulnar
collateral circulation is the modified Allen's test. This simple test provides an indication of
the functional dominance of the palmar arch in the hand and therefore adequacy of the ulnar
collateral supply to the hand with occlusion of the RA circulation. The test measures the time
it takes for hyperaemic reperfusion of the hand (thumb and fingers) to return on release of the
UA or RA after a period of brief occlusion (>30 seconds) of both arteries in the wrist
[7;8;10;16]. As ambient temperature can greatly influence this test through vasoconstriction
of the hand vasculatures in a cold room, the modified Allen’s test should be done in a
comfortable and stable ambient room temperature of about 22–24 degree Celsius. Both
arteries should be completely occluded using at least three fingers with the thumb providing
counter force on the dorsal surface of the wrist as shown in figure 2. This will provide a
stable grip on the wrist and also occlude a more proximally arising superficial palmar branch
of the RA, which can give a false negative test.
A negative modified Allen's test is indicated by a return of hyperaemic reperfusion of the
hand within 5 to 10 seconds. The test is considered positive if reperfusion takes more than 10
seconds, indicating poor ulnar collateral circulation and the RA should not be removed.


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The maximum cut-off limit for reperfusion to return varies from centre to centre, ranging
from 5 to 10 seconds. This variation and the fact that it has high false negative and false

positive rates make it some what unreliable. With a cut-off limit of 6 seconds, modified
Allen’s test has a poor sensitivity of 54.5%, specificity of 91.7% and a diagnostic accuracy of
78% [17]. However, by reducing the duration to less than 5 seconds as is used in our centre,
sensitivity of the test is increased to 65.8% with a diagnostic accuracy of 80% but a
specificity of 81.6% [17]. This will minimise the number of false negative tests. .

Figure 2. Modified Allen’s Test – Both RA and UA are occluded with 3 fingers each with counter-force
provided by the ipsilateral thumb on the dorsum of the wrist for up to 10 seconds while the patient
closes his hand. This will ensure that a recurrent superficial palmar artery arising early from the RA is
occluded, thus avoiding a false negative modified Allen’s test. The fingers occluding the UA are
released first and time taken for the patient’s hand and palm to become pink is measured. This is the
ulnar collateral reperfusion time and the modified Allen’s test is considered positive if the time to
reperfusion is more than 10 seconds. Both RA and UA are again occluded for 10 seconds, and this time
the RA is released to measure the reperfusion time of the hand and palm from the RA. This radial time
will give a comparison with the ulnar reperfusion time and also gives an indication of the dependency
of the palmar collateral circulation from the RA.

Other Methods of Assessing Adequacy of UA Circulation
To improve diagnostic accuracy, various other methods have been reported such as the
digital plethysmography to measure pulse-volume recording (PVR) or digital-brachial index
[18]. PVR ratio gives a percentage of RA contribution to pulsatile blood flow to the digits
and is a ratio of the area under the PVR curve with RA compression to that without
compression. Another method of modified Allen’s test is to use the pulse oxymetry to
measure time to reperfusion in terms of oxygen saturation of the thumb or digits [19]. This
avoids any visual inaccuracies in determining capillary reperfusion to the palm, fingers and
thumb. It is also possible to measure PVR ratio using pulse oxymetry but this may be
unreliable due to the self-calibrating properties of the instrument. This may give high false
negative readings.
A more definitive test is using Doppler ultrasound scan, which can detect any
abnormality of vascular distribution of the forearm and hand [20]. Dynamic Doppler also

Chee Fui Chong

6

measures flow in the RA and UA and the percentage of contribution of each artery to the
palmar arches [21]. Arteriography of the forearm and hand vasculature is probably the gold
standard as it will not only allow for visualisation of the vascular anatomy of the forearm and
hand but also allow for detection of any vascular anomaly [22].

Intra-Operative Assessment
Prior to division of the RA, an intra-operative assessment of distal RA stump flow could
be measured by occluding proximal RA flow using a bulldog clamp and making an incision
in the RA distal to the clamp and observing the amount of free flow through the incision [23].
If the free flow is adequate then the RA is divided. Similarly the distal RA backflow pressure
can be measured by inserting an 18 Ch needle attached to a manometer line into the RA distal
to the clamp. In our experience, a negative modified Allen’s test set at a five-second limit is
associated with a pressure drop in the distal RA of only 10-20 mmHg from systemic pressure.
We have only observed in one patient whose modified Allen’s test was equivocal at six to
seven seconds but an intra-operative distal RA pressure measurement showed a significant
drop of more than 50 mmHg. The RA was not removed in this case.
A simplified method is to feel for pulsation in the RA distal to the bulldog clamp, which
would indicate adequate ulnar collateral circulation [24].

Histopathology
Prevalence of pre-existing atherosclerotic disease in RA specimens taken at time of
surgery has been shown to be low [25-27]. Kaufer et al. reported a mean degree of pathology
for the RA of 0.89 on a 0 (none) to 4 (lumen completely obliterated) scale in comparison to a
scale of 0.30 for ITA [27]. Presence of diabetes, aorto-femoral disease, femoral-popliteal

disease, age and male gender correlated with an increase in RA pathology [27]. In another
study comparing RA with ITA and SV, there is a greater prevalence of mild intimal
thickening, medial sclerosis and medial calcification in RAs [26]. The significance of this on
long-term patency of RA grafts is uncertain and will need further evaluation.
However, a rare condition, which affects RA, is that of Monkeberg’s arteriosclerosis
which can vary from mild to severe involving the entire media [28]. This condition is
characterised by calcification and bone formation in the media of the arteries involved. We
have encountered two patients with severe form of this condition mainly affecting the distal
half of the RA. In both patients, we have avoided the use of the RA as grafts. In severe form
of Monkeberg's arteriosclerosis, the media and intima are almost completely replaced by
calcified osseous plaques. Such RA if encountered should be avoided. However, RA with
visible mild to moderate patchy calcification may be used if conduit availability is in doubt,
although the long-term patency of such RA grafts cannot be ascertained.


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7

In-Vitro Vasoreactivity Properties of RA
Early graft vasospasm posed a significant problem with the use of RA grafts, which may
lead to hypoperfusion syndrome in the early postoperative period or early graft occlusion. It
was thought to have accounted for its initial failure to be accepted as a suitable arterial graft
[1]. This vasospasm is visible during harvesting of the conduit and can be diffused or
segmental. Numerous in-vitro experiments have been conducted over the last two decades to
elucidate the endothelial and contractile properties of the RA in an effort to understand its
propensity to vasospasm and to find solution to overcome this [29-33].

Vasocontraction Profile
RA is classed as a muscular artery and has a thicker media than the ITA [34]. This is

reflected in in-vitro contraction studies where RA segments had significantly stronger
voltage-mediated (potassium chloride) and receptor-mediated (norepinephrine, serotonin,
thromboxane) contractions than ITA [33]. It also contracts significantly greater than ITA, to
Endothelin-1 and angiotensin II which are found in increasing plasma concentration during
cardiopulmonary bypass. Despite normalising for wall thickness, RA segments still exhibit
significantly greater contraction to angiotensin II and Endothelin-1 than ITA [31].
Characterization of adrenoceptors showed that the human RA is an α-adrenoceptordominant artery with a predominantly α1 function and little β-adrenoceptor function [29].
Therefore, the use of β-blockers will not likely evoke vasospasm of the RA. Postjunctional
α2-adrenoceptor is also functional. These greater contractile properties of RA may explain its
propensity to vasospasm.
Differences in vascular reactivity between proximal and distal segments of RA with a
greater contraction achieved in the proximal segment have also been reported [35]. This is
important, as most in-vitro experiments do not report on the segment of RA used.

Vasorelaxation Profile
Chardigny et al. reported endothelium-dependant relaxation in 70% of RA segments as
compared with 40% of ITA and 41.5% of RGEA [33]. He et al. reported similar degree of
endothelial dependant relaxation in RA segments as with ITA segments [31]. Cable et al.
however found that both receptor and non-receptor endothelial dependant relaxation in RA
segments were significantly reduced in comparison to ITA segments [36]. This conflicted
with earlier findings. Cable further reported that despite similar baseline production of NO,
stimulated production of NO was significantly reduced in RA segments when compared with
ITA segments [36]. This was confirmed by the findings of immunohistochemistry, which
demonstrated reduced expression of endothelium nitric oxide synthase (eNOS) in RA.
There are wide differences in methodology used in assessing in-vitro vascular reactivity
of arterial ring segments in organ baths. Particularly different harvesting and conduit
preparation techniques used may affect RA vascular reactivity. The methods of achieving


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resting tension vary greatly and thus the value obtained for resting tension of RA segments
ranged from 1.5g to 9g [33]. Similarly, most authors did not report on which segments (distal
or proximal) of RA were used. This may account for the discrepancy between the above data.
There is also evidence indicating that vasodilatation in RA is both NO-dependant and
NO-independent, unlike ITA which is completely NO-dependant [37]. Endothelium derived
hyperpolarising factor (EDHF) , synthesized by cytochrome oxygenase has been implicated
for NO-independent vasorelaxation which involved opening of Ca2+ activated potassium
channel(s) [37].

Harvesting Technique
Conventional Sharp Dissection and Ligaclipping of Side Branches
Problem of early graft spasm associated with handling during harvesting was partly
resolved with careful attention paid to harvesting of the conduit. Reyes et al. described a
careful technique of sharp dissections with minimal handling and using surgical clips to
occlude side branches with calcium channel blocker solution such as verapamil to rinse and
store the conduits prior to grafting [6].
A lazy S-curve skin incision is made on the volar surface of the forearm along the medial
border of the brachioradialis muscle, from the level of the bony styloid process of the radius
to a finger breadth level below the cubital crease. The dissection is carried right down to the
fascia covering the brachioradialis muscle. Care must be taken to avoid injury to the lateral
antebrachial cutaneous nerve at this point as the nerve courses down the forearm on the
surface of the fascia covering brachioradialis muscle, about 1cm lateral to the edge of the
brachioradialis muscle. This distance from the edge of the brachioradialis muscle can vary
from individual to individual.
The fascia covering the muscles is then divided at the medial margin of the
brachioradialis muscle and the latter muscle is reflected laterally with a self-retaining
retractor to reveal the RA pedicle beneath the belly of the brachioradialis muscle. The distal

third of the RA pedicle is covered only by fascia and subcutaneous fat as it lies medial to the
tendon of the brachioradialis muscle. Hence care must be taken to avoid injuring the RA
pedicle when dividing the overlying fascia. The RA is harvested as a pedicle with the two
venae comminantes. Side branches from the pedicle are occluded with ligaclips and divided
with scissors.
Two important nerves lie in close proximity to the RA pedicle in the distal half of the
forearm. The superficial radial nerve which lies 5 to 10 mm lateral to the RA pedicle under
the belly of the brachioradialis muscle in the distal half of the forearm. The median nerve in
the distal third lies just beneath and medial to the RA pedicle before it enters the hand
through the carpal tunnel fascia. Care must be taken to avoid injury to both nerves
particularly when using diathermy for harvesting.
This technique is used in majority of centres. Completely harvested, a full length of RA
is about 20–22cm in length and can reach most coronary target vessels or be divided into two
grafts [7]. However, it is slow and tedious and there is still a 5% incidence of spontaneous


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9

vasospasm with the RA during harvesting despite the careful techniques and use of
vasodilators.

Electro-Cautery
Electro-cautery has also been used in order to speed up the process of harvesting the RA
conduit. The process is similar to harvesting the pedicled LITA conduit by cutting and
coagulating side branches all along the RA pedicle. However, the gentleness of using of this
method to harvest the RA conduit is questionable as lateral spread of the heat generated may
cause thermal injury to the endothelium, especially when high-frequency electro-cautery is
used [38]. It is also a common error to use the diathermy tip to handle the RA pedicle while

the blade is still extremely hot.
Thus electro-cautery using a low-voltage diathermy is usually recommended and has not
been shown to cause any thermal injury to the endothelium or surrounding nerves [39;40]. In
experienced hands, it is a useful harvesting tool, which is quick, usually between 10-30
minutes and avoids excessive use of surgical clips [40].

Harmonic Scalpel (Ethicon, UK)
A safer, quicker and less traumatic method of harvesting the RA is with the use of the
Harmonic Scalpel (Johnson & Johnson, UK) [41]. The Harmonic Scalpel is an ultrasonic
surgical instrument for cutting and coagulating tissues with a blade vibrating at ultrasonic
frequency of 55.5 kHz. Cutting and coagulation occurs by the transference of mechanical
energy from the ultrasonic vibration of the blade to the tissue in contact, which is sufficient to
break tertiary hydrogen bonds and from the generation of the heat from internal cellular
friction, resulting from the high-frequency vibration of the tissue. Heat produced is localised
to the tissue in contact and unlike electro-cautery, lateral spread is low. However, this is
dependent on the duration of contact between the blade and tissue. Also, blood and fluid
within vessels and tissue have high heat capacity and will act as a sink, limiting further
spread of heat to nearby structures.
Haemostasis achieved is good and provides a bloodless field for harvesting with minimal
use of haemostatic clips [41]. Wound healing is similar to those achieved with conventional
methods. Several studies have shown minimal endothelial thermal injury with lower
incidence of vasospasm using this technique compared to RA harvested using diathermy
coagulation [38;42].
In a prospective randomized study to compare the above three techniques of harvesting
RA in 90 patients, Hata and colleagues suggested that conventional sharp dissection with
clips may be better for early post-operative forearm circulation with a significant reduction in
the incidences of hand numbness, when compared with harvesting with electro-cautery and
harmonic scalpel [43]. However, 12 months after harvesting, changes in forearm circulation
were similar between the three techniques.